pcgen.cdom.helper.BridgeListener.java Source code

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Here is the source code for pcgen.cdom.helper.BridgeListener.java

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/*
 * Copyright (c) Thomas Parker, 2017-18.
 * 
 * This program is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License along with
 * this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street,
 * Fifth Floor, Boston, MA 02110-1301, USA
 */
package pcgen.cdom.helper;

import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Objects;
import java.util.Set;

import org.apache.commons.lang3.tuple.ImmutablePair;

import pcgen.cdom.base.CDOMObject;
import pcgen.cdom.enumeration.CharID;
import pcgen.cdom.facet.base.AbstractSourcedListFacet;
import pcgen.cdom.formula.VariableChangeEvent;
import pcgen.cdom.formula.VariableListener;

/**
 * A BridgeListener converts from a VariableListener to then inject items into an
 * AbstractSourcedListFacet acting in the traditional Facet events.
 */
public class BridgeListener implements VariableListener<Object> {
    /**
     * The AbstractSourcedListFacet to which objects will be forwarded
     */
    private final AbstractSourcedListFacet<CharID, CDOMObject> variableBridgeFacet;

    /**
     * The CharID that this BridgeListener is serving
     */
    private final CharID id;

    /**
     * Constructs a new BridgeListener for the given CharID which will use the given
     * AbstractSourcedListFacet
     * 
     * @param id
     *            The CharID that this BridgeListener is serving
     * @param variableBridgeFacet
     *            The AbstractSourcedListFacet to be used as a bridge to the traditional
     *            Facet events
     */
    public BridgeListener(CharID id, AbstractSourcedListFacet<CharID, CDOMObject> variableBridgeFacet) {
        this.variableBridgeFacet = Objects.requireNonNull(variableBridgeFacet);
        this.id = Objects.requireNonNull(id);
    }

    @Override
    public void variableChanged(VariableChangeEvent<Object> vcEvent) {
        Object oldValue = vcEvent.getOldValue();
        Object newValue = vcEvent.getNewValue();
        /*
         * CONSIDER This is a hard-coding based on array - the format manager, which is
         * available from the event, might want to provide more insight. Currently, this
         * isn't possible, but it's something to think about with the FormatManager
         * objects going forward...
         */
        if (newValue.getClass().isArray()) {
            ImmutablePair<Set<Object>, Set<Object>> t = processIdentityDeltas((Object[]) oldValue,
                    (Object[]) newValue);
            for (Object o : t.getLeft()) {
                variableBridgeFacet.remove(id, (CDOMObject) o, vcEvent.getSource());
            }
            for (Object o : t.getRight()) {
                variableBridgeFacet.add(id, (CDOMObject) o, vcEvent.getSource());
            }
        } else {
            if (oldValue != null) {
                variableBridgeFacet.remove(id, (CDOMObject) oldValue, vcEvent.getSource());
            }
            variableBridgeFacet.add(id, (CDOMObject) newValue, vcEvent.getSource());
        }
    }

    private ImmutablePair<Set<Object>, Set<Object>> processIdentityDeltas(Object[] oldValue, Object[] newValue) {
        Set<Object> toAdd = Collections.newSetFromMap(new IdentityHashMap<>());
        Collections.addAll(toAdd, newValue);
        Set<Object> toRemove = Collections.newSetFromMap(new IdentityHashMap<>());
        Collections.addAll(toRemove, oldValue);
        if ((oldValue.length != 0) && (newValue.length != 0)) {
            //Note order sensitivity
            toRemove.removeAll(toAdd);
            Collections.addAll(toAdd, oldValue);
        }
        return new ImmutablePair<>(toRemove, toAdd);
    }

    @Override
    public int hashCode() {
        return id.hashCode() * 31 + variableBridgeFacet.hashCode();
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof BridgeListener) {
            BridgeListener other = (BridgeListener) obj;
            return id.equals(other.id) && variableBridgeFacet.equals(other.variableBridgeFacet);
        }
        return false;
    }
}